Genome-wide transposon mutagenesis in yeast

This unit provides comprehensive protocols for the use of insertional libraries generated by shuttle mutagenesis. From the basic protocol, a small aliquot of insertional library DNA may be used to mutagenize yeast, producing strains containing a single transposon insertion within a transcribed and translated region of the genome. This transposon-mutagenized bank of yeast strains may be screened for any desired mutant phenotype. Alternatively, since the transposon contains a reporter gene lacking its start codon and promoter, transposon-tagged strains may also be screened for specific patterns of gene expression. Strains of interest may be characterized by vectorette PCR (protocol provided) in order to locate the precise genomic site of transposon insertion within each mutant. A method by which Cre/lox recombination may be used to reduce the transposon in yeast to a small insertion element encoding an epitope tag is described. This tag serves as a tool by which transposon-mutagenized gene products may be analyzed further (e.g., localized to a discrete subcellular site).